Brewer&#39;s pitch composition



" Patented Sept. 12, 1944 2,358,207 BREWERS rrrcn ooMPosrrIoN Joseph N. Borglin, Wilmington, Del., assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware I No Drawing. Application December 6,1940,

. Serial No. 368,859

18 Claims.

This invention relates to pitches and more particularly to resinic base pitches such as are commonly used in the manufacture of brewer's pitch.

. These pitches, as their name implies, are used to line the inside of beer and ale kegs, also various other containers for spiritous liquids.

Brewers pitch, generally construed, comprises essentially a. natural resin from which about to about of the light oils, resin decomposition products, etc., have been removed. In addition, there may be added various plasticizers to obtain a product having the desired properties,

such as, the proper melting point, fast surface hardening characteristics, good adhesion, taste, color, odor, etc. The most commonly used materials of" this nature are mineral oil, rosin oil,

- parafiin, etc.

It has come to be recognized that the iinished pitch should have a melting point between about 50 C. and about 85 C. by the thermometer drop method so that it may be applied to the interior of the keg or removed from the keg with a minimum of trouble and .expense. The pitch must also be substantially odorless and tasteless, so that it will not impart a taint to the beer. Further, the pitch, after application to the inside of the barrel or keg, must not crystallize or check. This property is determined by a beating test which will detect any tendency of the pitch to crack loosefrom the'container. The reason for this requirement is obvious. If the pitch should check and crack loose from the container, there would be a consequent contamination of the liquid contained within the barrel; also the coating would no longer perform its function of sealing and protecting the contents. Again, the coating must not be such as to change the frothing characteristics of the beer or ale.

These coating are applied in various ways. For example, the container may be flushed with the pitch, or the pitch may be applied by spray application. This latter operation is usually car- 'ried out at temperatures of from about 200 C.

.the barrels are empty or not completely filled,

resulting in a coating which eventually becomes brittle and shows attendant disadvantages.

- Furthermore, its decomposition characteristics to about 225 0., hence the necessity for suflicient fluidity of the pitch at this temperature. Furthermore, the pitch must not show substantial decomposition at this temperature; for if that be the case, there are formed decomposition. products of light oils, acid vapors, etc., which, after cooling, condense on the inner surface of the barrel and impair the taste of the beer, etc.

In the past, rosin has been the chief resinic component .of brewer's pitch, both in the form of gumand wood rosin. However, with the use of these materials, although there is an improvement in the taste and odor of the resulting pitch, if the rosin has been highly refined, there remains much to be desired in this direction. Also,

- there is the well-known tendency of rosin to oxidize. This oxidation takes place whenever upon spraying at elevated temperatures are not satisfactory. As has been previously stated, all the prior artv pitches have a rather low melting point, i. e., one within the range of from about 50 C. to about 85 C. It is sometimes necessary to produce a pitch. with a comparatively high melting point, particularly when the barrels or kegs in which it is to be used aresubject to extremely abnormal temperatures. Finally, the cost of the most interesting of the materials suggested to overcome the faults of rosin is such that their use. is prohibitive, at least at the present time.

Hence, an object of my invention is to produce a brewer's pitch which will be highly resistant to oxidation and capable of substantially retaining its original elasticity. r

, It is a further object of my invention to produce a brewer's pitch which will be odorless and tasteless so that there will be no consequent tainting of the brewed product.

A still further object is to produce a brewer's pitch which will have a comparatively high melting point.

Another object is to produce a material which can be manufactured economically as compared with the prior art methods. I

Still other objects will appear hereinafter.

.The objects of my invention are in general accomplished by using as the resinic ingredient of the pitch a polymerized natural resin which has been further subjected .to the processes of heat treatment and the subsequent removal of the light oils and resin decomposition products to the extent of not more than about 25 by weight of said polymerized natural resin. I haye found that a brewer's pitch made by the use of such a polymerized natural resin, such as, for example, polymerized rosin, shows highly improved characteristics over the formerly used pitches. The product is substantially resistant to oxidation, it is odorless, tasteless and gives a comparatively inexpensive coating.

My experiments have shown that when an unsaturated natural resin is polymerized by any of the known methods, such as, for example, by treatment wiih sulfuric acid while the resin is dissolved in a suitable solvent, a product individual polymerized natural resin will absorb will depend upon the conditions under which the polymerizing reaction is carried out, i. e., the time of treatment, the concentration of the catalyst, the type of catalyst, etc. While any polymerized natural resin may be used in accordance with the present invention to produce imtofore noted, it is quite often necessary in ac- A T cordance with this invention to use a plasticizproved pitches, it is preferred to use a natural resin wherein the polymerization has proceeded to the point that there are present from about to 100% of the polymer of the resin acids.

It is fundamental, however, that the extent to which the improved properties will be realized will depend upon the degree of. polymerization.

According to this invention, then, a quantity of a polymerized natural resin is subjected to a heat treatment. The operable range of temperatures for this S p is from about 200 C. to about 350 0.; however, it is preferable to use a temperature within the range of from about 250' C. to about 325 C. Atmospheric pressure may conveniently be used; however, this operation may-be carried out at pressures thereabove or below. The period of heat treatment may vary within the range of from about V2 to about '24 hours, preferably within the range of from about 1 toabout 12 hours. The heat treatment may v be carriedout with the heated resin in contact with an inert gas; such as, for example, CO1,

to prevent extreme oxidation at the elevated temperature.

An integral part of this invention is the removal of the decomposition products formed as 'a. consequence of the heat-treatment along with any odor and taste imparting ingredients originally present inthe resin. Some of these products are removed by distillation collaterally with the heat-treatment, and substantially complete removal can be effected by distillation. However, -inasmuch as there is always a certain amount of decomposition occurring during, distillation, it is preferred to effect the removal by sparging with a gas which is-inert to the reaction mixture, such as, for example, CO2, ni-

trogen, steam, etc. The sparging' may be done under a vacuum or at atmospheric pressure.

The processes of heat treatment and removal may be conducted in such a manner that up to g about by weight of the resinous material used has'been removed. However, it is preferable to operate within the range wherein from about 5%; by weight to about 15% by weight of the resinous material is removed.

According to my invention, then, a quantity of a polymerized resin, such as, for example, poly- -"merized rosin, is placed in a copperstill or other suitable non-ferrous container. The rosin is then heated to a temperature of, for example, about 300. C. for a period of, for example, 6 hours. The melted mass is then sparged under vacuum or at atmospheric pressure with steam -or some other gas which is inert to the reaction mixture. This procedure maybe altered as desired to produce a pitch having different physical characteristics. Long heating time with short sparging time produces a pitch with a low-melting point and a low acid number. Long heating with long sparging under vacuum produces a pitch of medium melting point and a low acid number. Short heating time with medium long parging time produces a pitch with a higher acid numberand a higher melting point.

If a pitch having a high melting point is desired. the product Just obtained maybe used While'a particular grade of polymerized rosin was used in the examples,-it will be understood 1 ing agent in conjunction with the heat treated lymerized resins disclosed above in the plastic mass. These plasticizers include paraflin wax, mineral oils, rosin oil, etc. and may be incorporated in any desired proportions to make the finished pitch. However, it is preferred that the final product contain not more than about 15% by weight of paraflin wax, not more than about 30% by weight of refined mineral oil or not more than about 30% by weight or rosin oil. It is, of course, possible to use various combinations of the aforementioned materials as the plasticizing agent. If rosin oil is used as a plasticizer, desirably, a rosin oil obtained from polymerized rosin is used. It is also contemplated that a pitch made from ordinary rosin be blended with a pitch made from polymerized rosin. It should be noted, however, that in all cases where additional ingredients are used, care should be taken thatthe added ingredients be highly refined and be without odor and taste.

The brewer's pitch of the present invention is characterized by its comprising an atleast partially polymerized natural resin which is substantially free from light oils and resin acid decomposition products; conversely, such a pitch is characterized by its comprising an at least partially polymerized natural resin which is substantially free of odor and taste imparting compounds.

Wherever the term "rosin". is used herein, it should be understood to include both wood and gum rosin in any of the grades commonly obtainablealso theresin acids which are obtained from the above rosin bases, such as, for example, abietic, pimaric, sapinic, sylvic, etc.

Any of the resinous products obtained from the members of the genus of trees known as Pinaceae are particularly suitable as a source of the natural resins specified above.

It is further to be noted that although polymerized rosin the preferred ingredient in pitches made by virtue of my discovery, the invention is not to be restricted to the use of that material. Any natural resin which can be polymerized by any of the known processes may, after methods of preparing a brewers pitch embodying the principles of the present invention, which,

however, are not to be taken as limiting. In these examples the polymerized rosin used had the following characteristics:

Acid number 151-155 Color 1 14-26 Amber- Grade x to WG Melting point (drop) C-.. 98-101 without modification. However, to obtain a 7| that theinventicn is by no means there-1 to, but on the contrary is applicable to the use of any polymerized rosin.

Example 1 Two hundred and fifty parts by weight of poly- Example 2 Three parts by weight of paraflin wax and 15 parts by weight of mineral oil (Nujol) are intimately mixed with 82 parts by weight of the material obtained in Example 1. a highly satisfactory brewer's pitch. It is odortive feature of this new type of pitch is the lack of crystallization of the resin on cooling or upon evaporation from a volatile solvent.v This is highly important in the production of a. barrel coatingwhich will have moderately good durability. Finally, the essential ingredient of my invention is;much less expensive than are most of the other materials which have been suggested to overcome the disadvantages of ordinary gum or wood rosin.

It will be understood that the brewers pitch hereinbefore desoribedis suitable for coating any container for spiritous liquids whether it be made of wood, metal, etc., and without regard to its size.

It will be understood that the details and examples hereiubefore set forth are illustrative only and that the invention as broadly described The product is less,-tasteless and retains its original elasticity over a long period of time.

' Example 3 product is then allowed to. cool. This product has an acid number of 69.0 and a melting point of 107 C. by the thermometer drop method. It is found to have excellent properties when used as a brewers pitch.

' Example 4 Twelve parts by weight of rosin oil are intimately mixed with 88' parts by weight of the material obtained in Example 3. A material is obtainedwhich has very satisfactory properties for use as a brewers pitch.

Example 5 7 Three hundred parts by weight of polymerized rosin are heated up to 300 C. at atmospheric pressure. Themass is then sparged with CO2 at atmospheric pressure for hour as the temperature drops from 300 C. to 207 C. Then the product is allowed to cool. This product has an acid number of 137.5 and a melting point of 102.0 C. by the thermometer'drop method. It may be used as a brewers pitch without further modification. Example 6 Three parts by weight of paraflin wax and 15 parts by weight of mineral. oil (Nujol) and 82 parts by weight of the material obtained in Ex- ,ple 5 are intimately mixed together. A material highly satisfactory for use as a brewers pitch is obtained.

The pitches made by processes embodying my invention possess new and unusual properties when compared with those made by the prior art. They are all substantially resistant to oxidation and do not become hard and brittle with age. Then, the incorporation of the polymerized resinic component in the pitch gives a resulting product having less odor and taste than one having a straight rosin base due in part to the lower vapor p e of the polymerized ingredient addi- 75 about 5% to about 15% by weight of said polyand claimed is in no way limited thereby.

What I claim and desire to protect by Letters Patent is: v 1. A brewer'spitch comprising at least partially polymerized rosin'which has been further subjected to the processes of heat treatment at a temperature within the range of from about 200 C. to about 350 C. for a period of from about hour to about 24 hours and the subsequent removal of the light oils and resin decomposition products to the extent of from about 5% to not more than about 25% by weight of said polymerized rosin.

2. A brewers pitch comprising at least partially polymerized rosin which has been further subjected to the processes of heat treatment at a temperature within the range of from about 250 C. to about 325 C. for a period of from about 1 hour to about 12 hours and the subsequent removal of the light oils and resin decomposition products to the extent of from about 5% to not more than about 25% by weight of said polymerized rosin.

3. A brewer's pitch comprising, rosin which has been polymerized tocontain from about 10% to 100% of the polymer of the unsaturated rosin acids present and which has been further subiected to theprocesses of heat treatment at a temperature within the range of from about 250 C. to about 325 C. for a period of-- from about 1 hour to about 12 hours and a subsequent removal of the light oils and resin decomposition products to the extent of from about 5% to not more than about 25% by weight of said polymerized rosin.

4. A brewers pitch comprising rosin which has been polymerized to contain from about 10% to 100% of the polymer of the unsaturated rosin acids present and which has been further subjected to. the processes of heat treatment at a temperature within the range of from about 250 C. to about 325 C. for a period of from about 1 hour to about 12 hours and the subsequent removal of the light oils and resin decomposition products to the extent of from about 5% to about 15% by weight of said polymerized rosin.

5. A brewers pitch comprising rosin which has been polymerized to contain from about 10% to of the polymer of the unsaturated rosin acids present and which has-been further subjected to the processes of heat treatment at a temperature within the range of from about 250 C. to about 325 C. for a period of from about 1 hour to about 12 hours and the subsequent removal of the light oils and resin decomposition. products to the extent of from composition products to the extent of from,

about 5% to not more than about 25% by weight of said polymerized rosin, and a plasticizlng went. 1 7. A brewer's pitch comprising rosin which .has been polymerized to contain from about 10% to 100% 01' the polymer the unsaturated rosin acids present and which has been further subjected to the processes of heat treatment at a temperature within the range of from about 250 C. to about 325 C. for a period of from about 1 hour toabout 12 hours and the subsequent removal of the light oils and resin decomposition products to the extent of from about 5% to not more than about 25% by weight 01' said polymerized man, and parailin wax.

8. A brewer's pitch comprising rosin which has been polymerized to contain from to 100% of the polymer of the unsaturated rosin acids present and which has been further subjccted to the processesot heat treatment at a temperature within the range of from about 250 C. to about 325 C. for a period of from about 1 hour to about 12 hours and the subsequent removal of the light oils and resin decomposition products to the extent of from about 5% to not more than about 25% by weight of said polymerized rosin, and a mineral 'oil.

9. The method for making a brewer's pitch which includes the steps of subjecting an at least partially polymerized rosin to the processes 01' heat treatment at a temperature within the range of from about 200 C. to about 350 C. for a period of from about hour to about 24 hours 'and the subsequent removal of from about, 5%

to not more than about 25% by weight'oi said polymerized rosin.

10. The method for making a brewer's. pitch which includes the steps of subjecting rosin,

which has been polymerized to contain. from about 10% to about 100% 01' the polymer oi the unsaturated rosin acids present, to the processes of heat treatment at a temperature within the range of from about 250 C. to about 325 C. tor

a period of from about 1 hour'to'about 12 hours and the subsequent removal of the light oils and.

resin decomposition products to the extent oi from about 5% to about by weight 01' said polymerized rosin by sparging with a gas which is inert to the reaction mixture.

11. A brewer's pitch comprising rosinvwhich I has been polymerized to contain from about 10% .to 100% of the polymer of the unsaturated n acids present and which has been further mjected to the processes of heat treatment at a temperature within the range of from about 250 C. to about 325 C. for a period of from about .1 hour to about 12 hours and the subsequent removal of the light oils and resin decomposition products to the extent of from about 5% to'not more than about by weight of said polymerized rosin, and paraflin wax present in such an amount that not more than 15% by weight will be contained i e the final product.

merized romn by sparging with a gas which is 12. -A brewer's pitch comprising rosin which has been polymerized to contain from 10% to 100% or the polymer of the unsaturated rosin acids present and which has been iurther subjected to the processes of heat treatment at atemperature within the range 01' from about 250 C, to about 325 C. for a period of from about 1- hour to about 12 hours and the subsequent removal oi the light oils and resin decomposition 10 products to the extent of from about 5% to not more than about 25% by weight of said polymerized rosin, and a mineral oil present in such ah amount that not more than by weight will be contained in the final product. a

13. A brewer's pitch comprising at leastpartially polymerized rosin which has been further subjected to the processes of heat treatment at a temperature within the range of from about 200 C. to about 350 C. for a period'of from about ,5 hour to about 24 hours and the subsequent removal of the light oils and resindecomposition products to the extent-oi from about 5% to not more than about 25% by weight of said D0 8- merized rosin and a ,plasticizing agent.

14. The method for making a brewers pitch which includes the steps of subjectingan at least partially polymerized rosin to the processes of heat treatment at a temperature within the range 01 from about 250 C. to about 325 C. for so a period of from about '1 hour to about 12 hours and the subsequent removal of .the light oils. and resin decomposition products tothe extent of from about 5% to not more than about 25% by vweight of said polymerized rosin. 15. The method, for making a brewer's pitch which includes the steps of subjecting a rosin which has been polymerized to contain. from about 10% to 100% of the polymer of the unsaturated rosin acids present and which has been 40 further subjected to the processes oi heat treat:- ment at a temperature within the range of from about 250 C; to about 325 C. for a-period of from about 1 houigto about 12 houisfajn'd the subsequent removal or the. light oils and resin decomposition products to the extent otirom about 5% to not more than about 25% by weight of said polymerized rosinl 16.. The method-for making a brewer's pitch which includes the steps 01' subjecting an at least partially polymeri'zed'rosinrto'the processes of heat treatment at a temperature within the range oi from about 200 C. to about 350 C. for a period 0! from about hour to about 24 hours, subsequently removing from about 5% to' not more than about 25% of said polymerized rosin and adding a plasticizing agent.

17. The method for making a brewer's pitch which includes the steps of subjecting an at least partially polymerized rosin to the '5 heat treatment at a temperature within the range of from about 200 C. to about 350 C. for a period 01 from about )5 hour to about 24 hours. subsequently removingfrom about 5% to not more than about 25% of said polymerized rosin and adding paramn wax. A

18. The method for. making a brewer's pitch which includes the steps of subiecting'an at least partially polymerized rosin to. the processes ot heat treatment at a temperature within the range of vfrom about 200 C. to about 350 C. for a period 01' from about hour to about 24 hours, subsequently removing from about 5% to not more than about 25% of said polymerized rosin and addingmineral oil.

JOSEPH N. BOR GLIN.

processe or, 

